Apply Jorge's example query to other select-intensive RethinkDB queries

[pzduniak]

r
.table('labels')
.getAll(owner, { index: 'owner' })
.map(function (label) {
 return r.table('threads')
 .getAll(label('id'), { index: 'labels'})
 .coerceTo('array')
 .do(function (threads) {
 return label.merge({
 'total_threads_count': threads.count(),
 'unread_threads_count': threads.filter(function (thread) {
 return thread('is_read').not().and(
 thread('labels').contains(function (label) {
 return r.expr(spamTrashSent)
 .map(function (row) { return row('id'); })
 .contains(label);
 }).not()
 )
 }).count()
 });
 });
});